Exhaust gas purification system

Abstract

The present invention relates to a technology of reducing nitrogen oxide (NOx) which is harmful discharge gas discharged from an internal combustion engine or a combustor, and to an exhaust gas purification system which inputs solid ammonium salt such as ammonium carbamate or ammonium carbonate into a reactor, thermally decomposes and converts the solid ammonium salt into the ammonia by using engine cooling water, exhaust gas, or an electric heater, which are installed in the reactor, and reduces the nitrogen oxide included in the exhaust pipe on a selective catalytic reduction into nitrogen by injecting the ammonia by using a pressure regulator and a dosing valve.

What is claimed is: 
     
       1. An exhaust gas purification system comprising:
 a main reactor configured to produce ammonia from solid ammonium salt; 
 a dosing module connected to the main reactor to adjust a supply of the ammonia produced in the main reactor; 
 an injection nozzle installed in an exhaust pipe to inject the ammonia supplied from the dosing module to the exhaust pipe; and 
 an auxiliary reactor having an internal space in which solid ammonium is accommodated, and provided at an ammonia supply line, which connects the main reactor and the dosing module, along a length direction of the ammonia supply line, 
 wherein the main reactor comprises, a housing of which one side is formed to be opened; a solid ammonium salt cartridge provided in the housing; a cover coupled to the housing so that the opened one side of the housing is sealed; and an outlet formed at the other side of the housing and connected to the ammonia dosing module, and 
 wherein the auxiliary reactor includes a fourth heating means which heats the solid ammonium salt, and the auxiliary reactor produces ammonia until ammonia is discharged from the main reactor. 
 
     
     
       2. The exhaust gas purification system of  claim 1 , further comprising:
 a gas supply device configured to supply gas to an ammonia supply line connected between the main reactor and the dosing module. 
 
     
     
       3. The exhaust gas purification system of  claim 2 , wherein:
 the gas supply device is an air supply device which supplies air to the ammonia supply line. 
 
     
     
       4. The exhaust gas purification system of  claim 3 , wherein:
 the air supply device is any one of an air tank, a blower, and an air compressor. 
 
     
     
       5. The exhaust gas purification system of  claim 2 , wherein:
 the gas supply device is an exhaust gas supply device which supplies exhaust gas to the ammonia supply line. 
 
     
     
       6. The exhaust gas purification system of  claim 5 , wherein:
 the exhaust gas supply device supplies the exhaust gas at a rear end side of a diesel particulate filter provided at the exhaust pipe to the ammonia supply line. 
 
     
     
       7. The exhaust gas purification system of  claim 5 , wherein:
 the exhaust gas supply device is a blower, or an air compressor. 
 
     
     
       8. The exhaust gas purification system of  claim 2 , wherein:
 the gas supply device is an outside air supply device which supplies outside air, which is supplied to a cylinder by a supercharger, to the ammonia line. 
 
     
     
       9. The exhaust gas purification system of  claim 8 , wherein:
 the outside air supply device is a blower, or an air compressor. 
 
     
     
       10. The exhaust gas purification system of  claim 2 , wherein:
 an opening and closing valve is positioned between the gas supply device and the ammonia supply line. 
 
     
     
       11. The exhaust gas purification system of  claim 10 , wherein:
 the opening and closing valve is a two directional (two-way) valve, or a three directional (three-way) valve. 
 
     
     
       12. The exhaust gas purification system of  claim 1 , wherein:
 a first heating means configured to heat the solid ammonium salt is provided at the main reactor. 
 
     
     
       13. The exhaust gas purification system of  claim 12 , wherein:
 the first heating means uses at least one of an electric heater, exhaust gas, and cooling water as a heat source. 
 
     
     
       14. The exhaust gas purification system of  claim 1 , wherein:
 at least one of an exhaust gas flow path through which exhaust gas flows, and a cooling water flow path through which cooling water flows, is formed at the main reactor. 
 
     
     
       15. The exhaust gas purification system of  claim 14 , wherein:
 the exhaust gas flow path is connected to an exhaust gas inlet pipe into which the exhaust gas flows from the exhaust pipe, and an exhaust gas outlet pipe which allows the flowing exhaust gas to flow out to the exhaust pipe. 
 
     
     
       16. The exhaust gas purification system of  claim 15 , wherein:
 a blower is coupled to the exhaust gas outlet pipe. 
 
     
     
       17. The exhaust gas purification system of  claim 1 , wherein:
 the main reactor comprises 
 a sensor unit provided at the cover. 
 
     
     
       18. The exhaust gas purification system of  claim 17 , wherein:
 the sensor unit includes at least one of a pressure sensor, and a temperature sensor. 
 
     
     
       19. The exhaust gas purification system of  claim 1 , wherein:
 a third heating means is provided at the dosing module. 
 
     
     
       20. The exhaust gas purification system of  claim 19 , wherein:
 the third heating means uses at least one of an electric heater, exhaust gas, and cooling water as a heat source. 
 
     
     
       21. The exhaust gas purification system of  claim 1 , wherein:
 the dosing module comprises 
 at least one of an exhaust gas flow path through which exhaust gas flows and a cooling water flow path through which cooling water flows. 
 
     
     
       22. The exhaust gas purification system of  claim 1 , wherein:
 the dosing module comprises 
 a valve body, 
 an ammonia flow path formed to penetrate the valve body, 
 a pressure regulator provided at the ammonia flow path to adjust ammonia flow pressure, 
 an adjusting valve provided at the ammonia flow path to adjust a discharge amount of the ammonia, and 
 a temperature sensor provided at the valve body. 
 
     
     
       23. The exhaust gas purification system of  claim 1 , wherein:
 the fourth heating means is an electric heater. 
 
     
     
       24. The exhaust gas purification system of  claim 1 , wherein:
 the auxiliary reactor is heated at the same time of starting an engine, and a heating operation is stopped at the same time of stopping the engine. 
 
     
     
       25. The exhaust gas purification system of  claim 1 , wherein:
 the auxiliary reactor is heated at the same time of starting an engine, and heated before the engine is stopped. 
 
     
     
       26. The exhaust gas purification system of  claim 1 , further comprising:
 a selective catalytic reduction installed in the exhaust pipe to reduce the nitrogen oxide into nitrogen and water by mixing nitrogen oxide included in exhaust gas with the ammonia injected to the exhaust pipe; and 
 an electronic control unit connected to the main reactor and the dosing module to control production and supply of the ammonia. 
 
     
     
       27. The exhaust gas purification system of  claim 26 , wherein:
 a fifth heating means provided at the housing and connected to the electronic control unit. 
 
     
     
       28. The exhaust gas purification system of  claim 27 , wherein:
 the fifth heating means uses at least one of an electric heater, exhaust gas, and cooling water as a heat source. 
 
     
     
       29. The exhaust gas purification system of  claim 28 , further comprising:
 a temperature sensor and a pressure sensor installed at the housing and connected to the electronic control unit. 
 
     
     
       30. The exhaust gas purification system of  claim 26 , further comprising:
 a nitrogen oxide concentration measurement sensor installed at a rear end of the exhaust pipe where the selective catalytic reduction is installed. 
 
     
     
       31. The exhaust gas purification system of  claim 26 , further comprising:
 an exhaust gas temperature sensor installed at a front end of the exhaust pipe where the selective catalytic reduction is installed, 
 wherein a temperature of the dosing module is adjusted in accordance with the measured temperature. 
 
     
     
       32. The exhaust gas purification system of  claim 1 , wherein:
 the solid ammonium salt is ammonium-carbamate (NH 2 COONH 4 ) or ammonium-carbonate ((NH 4 ) 2 CO 3 ).